Fig. 4: Synthetic Utilities.
From: Harnessing the β-boron effect for regioselective Ru-catalyzed hydrosilylation of internal alkynes
A gram-scale synthesis. B synthetic applications. Reaction conditions: a 6 (0.1 mmol, 1.0 equiv.), NIS (0.2 mmol, 2.0 equiv.), 2,6-lutidine (0.7 equiv.), HFIP (0.2 M), 0 oC; b 73 (0.1 mmol, 1.0 equiv.), PhB(OH)2 (0.3 mmol, 3.0 equiv.), Pd(PPh3)2Cl2 (10 mol%), SPhos (15 mol%), K2CO3, (0.15 mmol, 1.5 equiv.), Ag2O (0.25 mmol, 2.5 equiv.), 4 Å MS, THF (0.5 M), 60 oC; c 73 (0.1 mmol, 1.0 equiv.), phenylacetylene (0.15 mmol, 1.5 equiv.), Pd(PPh3)2Cl2 (5 mol%), CuI (10 mol%), Et3N (0.3 mmol, 3.0 equiv.), DMF, (0.5 M), rt; d 73 (0.1 mmol, 1.0 equiv.), ethyl acrylate (0.2 mmol, 2.0 equiv.), Pd(PPh3)4 (5 mol%), Et3N (2.0 equiv.), MeCN (0.5 M), 70 oC; e 6 or 3 or 49 (0.1 mmol, 1.0 equiv.), pinnacol (0.5 mmol, 5.0 equiv.), NaHCO3 (0.5 mmol, 5.0 equiv.), CH3OH, 50 oC, then PhCHO (0.11 mmol, 1.1 equiv.), Et2O (0.2 M), rt.; f 49 (0.1 mmol, 1.0 equiv.), pinnacol (0.5 mmol, 5.0 equiv.), NaHCO3 (0.5 mmol, 5.0 equiv.), CH3OH, 50 oC, then NaBO3·4H2O (0.3 mmol, 3.0 equiv.), THF/H2O (1:1, 0.2 M), rt; g 77 (0.1 mmol, 1.0 equiv.), methyl 4-iodobenzoate (0.15 mmol, 1.5 equiv.), Pd2dba3 (5 mol%), TBAF (2.0 equiv.), THF (0.2 M), 60 oC.
